I think we should go with unique shortcuts for each action, mainly because Joplin doesn’t have a lot of shortcuts. Another benefit is the user don’t have to change the focus beforehand executing a keyboard shortcut.
As I was saying, currently all shortcuts are enabled when the user is editing the note body. That’s why I didn’t include a context field in the mock-ups. (Even if I did, then it’d be “Default” for everything…) Therefore having context-limited shortcuts are not useful at the moment, in my humble opinion.